Final answer:
Humans and chimpanzees diverged from a common ancestor about 6 million years ago, marking the beginning of the hominin lineage. Fossil evidence suggests that this divergence could have happened between 5 and 7 million years ago. The study of hominin evolution, including the development of bigger brains and bipedalism, is an ongoing and evolving field of research.
Step-by-step explanation:
Human-Chimpanzee Divergence
Humans diverged from their common ancestor with chimpanzees roughly 6 million years ago. This evolutionary milestone marked the beginning of the hominin lineage, which encompasses all species that evolved after this split, including our own species, Homo sapiens. Notable hominins, such as Australopithecus, Homo habilis, and Homo erectus, show a progression towards traits that define modern humans, such as increased brain size and bipedalism. Fossils, like the Sahelanthropus tchadensis, provide evidence that our last common ancestor with chimps and the divergence point may date back even further, to between 5 to 7 million years ago.
The evolution of hominins continued over the millennia with significant developments occurring during the last 800,000 years, during which Homo sapiens evolved with much bigger brains and smaller faces compared to their ancestors. While humans and chimpanzees now have distinct evolutionary paths, the study of when exactly humans diverged from chimps is an ongoing field of research, with new fossil discoveries adding further insights into our complex evolutionary history.